I don't see how a bomb with a 500 yard kill radius can be confused for a "pipe bomb."
Of course you can't put too much stock in the initial news reports, when nobody really knows yet what's going on. That being said, 500 Yards is probably pushing it a little.
A big pipe bomb? You do know that pipes comes in diff shapes and sizes, right? And that there are different types of explosive materials, different composite pipes, etc?
And, again, what possible motivation does the US Attorney for NJ and the head of the FBI have for embellishing? Had he said 400 feet, or 250 feet, it would have had the same effect.
Sorry, I just don't buy that they sat around, pre-news conference, and said, "So it only would have a radius of 200 feet? Nah, that's not eye-catching enough, so let's make it 500 feet instead."